Initial studies were conducted in the physical facilities of the Behavioral Pharmacology Research Unit at Johns Hopkins University medical School in collaboration with Dr. R.R. Griffith which provided some research support. For example, multiple measures of cigarette smoking, subjective effect, and physiologic effect were collected during ad libitum smoking sessions in normal volunteers following administration of mecamylamine, naloxone, or marijuana. Presently, basic measures of cigarette smoking are being collected from all subjects on the Clinical Research Unit and data analyses have begun. This database-type of study appears to be providing the opportunity to quantitate the effects of a wide range of variables on cigarette smoking (i.e., atropine administration, cocaine withdrawal, buprenorphine administration, and passive tobacco smoke exposure).